INVESTIGATION OF MATERIAL REMOVAL IN PULSED-LASER DEPOSITION OF CERAMICS

The material removal of the ceramics alumina and zirconia by CO2 and e xcimer laser radiation is investigated both experimentally and theoret ically. The experimental investigations include microbalance measureme nts of the mass loss of the target as a measure of mass removal as wel l as high speed photography and emission spectroscopy as a measure of geometry and dynamics of the vapor-plasma state generated. The theoret ical investigations combine the laser-induced phase transition from so lid state to vaporized gas of the ceramic targets and the dynamics of the emerging vapor-plasma state. The plasma is described in a two-flui d approximation by use of non-dissipative,Gas-dynamical equations inco rporating absorption of laser radiation in the plasma and the dynamics of its ionization slate. Experimental and calculated results show two plasma regions above the target surface in the pressure regime 10(-2) -1 x 10(0) mbar used for thin him deposition: one attached to the irra diated target surface and another concerning the developing and propag ating shock front. The calculated and the experimental mass loss vs, t he laser fluence are in qualitative agreement but with the maximum shi fted for the calculations to smaller fluences.